My goal was to learn enough to get my GWS Slow Stick up and down in one piece without the aid of a seasoned flyer.
I went cheap and got RC Simulator from Tower for about $15. You need a game pad that has joy sticks or can get some kind of interface. I just used a game pad.
I spent a lot of time on it and it taught me enough to have a very successful first flight.
If my intent was to learn to fly glo planes by myself, I would have probably gone to one of the name brand sims.
I guess you've heard that there is a new version of Realflight to be sold soon. What that means, though, is anyones guess!